1. Field of the Invention
The present invention relates to antenna reflectors, and, more particularly, heated antenna reflectors.
2. Description of the Related Art
A reflector, commonly called a dish, is generally a parabolic section having a round or elliptical configuration. A reflector functions to gather radio or microwave frequency energy transmitted from the feedhorn or through the ambient environment from an external transmitter. The reflector can thus be used to receive and transmit signals to and from the satellite system. Reflectors are usually located outdoors, where snow and ice may collect on the receiving or concave side, degrading the performance of the reflector.
It is known to heat the front surface of a reflector with an electrical heating device in order to keep it clear of ice and snow. The heating device can be in the form of electrodes or resistance wire that is attached to the front surface of the reflector, embedded in the front surface, or attached to the back surface of the reflector. Further, it is known to energize the heating device with power line voltage, with 120 and 240 volts being common in the United States.
A problem is that these heaters are somewhat inefficient in terms of electrical power usage. In order to ensure that enough heating power is provided to melt the ice at the coldest operating temperatures, the heaters are configured to provide a level of power that is far in excess of what is required at the upper end of the range of operating temperatures. Besides wasting electricity, this excess dissipation of power can raise the temperature of the heating device and/or the reflector to a level where physical damage is done and the useful lives of the heating device and/or the reflector are reduced.
Another problem is that power line voltage varies widely through out the world. A different heater configuration is required with each different power line voltage in order to provide the reflector surface with a precise, desired level of electrical heating power.
What is needed in the art is an improved reflector heater assembly which can provide an appropriate level of electrical heating power at any ambient temperature and with any power line voltage.